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Author |
Ong, W.J. et al; Domingo-Pardo, C. |
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Title |
Low-lying level structure of Cu-56 and its implications for the rp process |
Type |
Journal Article |
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Year  |
2017 |
Publication |
Physical Review C |
Abbreviated Journal |
Phys. Rev. C |
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Volume |
95 |
Issue |
5 |
Pages |
055806 - 8pp |
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Keywords |
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Abstract |
The low-lying energy levels of proton-rich Cu-56 have been extracted using in-beam gamma-ray spectroscopy with the state-of-the-art gamma-ray tracking array GRETINA in conjunction with the S800 spectrograph at the National Superconducting Cyclotron Laboratory at Michigan State University. Excited states in Cu-56 serve as resonances in the Ni-55(p,gamma)Cu-56 reaction, which is a part of the rp process in type-I x-ray bursts. To resolve existing ambiguities in the reaction Q value, a more localized isobaric multiplet mass equation (IMME) fit is used, resulting in Q = 639 +/- 82 keV. We derive the first experimentally constrained thermonuclear reaction rate for Ni-55(p,.) Cu-56. We find that, with this newrate, the rp processmay bypass the (56)Niwaiting point via the Ni-55(p,gamma) reaction for typical x-ray burst conditions with a branching of up to similar to 40%. We also identify additional nuclear physics uncertainties that need to be addressed before drawing final conclusions about the rp-process reaction flow in the Ni-56 region. |
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Address |
[Ong, W. -J.; Langer, C.; Montes, F.; Bazin, D.; Brown, B. A.; Browne, J.; Cyburt, R.; Deleeuw, E. B.; Gade, A.; Keek, L.; Kontos, A.; Lemasson, A.; Lunderberg, E.; Meisel, Z.; Noji, S.; Nunes, F. M.; Perdikakis, G.; Pereira, J.; Quinn, S. J.; Recchia, F.; Schatz, H.; Scott, M.; Simon, A.; Spyrou, A.; Stevens, J.; Stroberg, S. R.; Weisshaar, D.; Wheeler, J.; Wimmer, K.; Zegers, R. G. T.] Michigan State Univ, Natl Superconducting Cyclotron Lab, E Lansing, MI 48824 USA |
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Publisher |
Amer Physical Soc |
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Language |
English |
Summary Language |
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Original Title |
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Series Title |
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Abbreviated Series Title |
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Series Volume |
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Series Issue |
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Edition |
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ISSN |
2469-9985 |
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Expedition |
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Conference |
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Notes |
WOS:000401655000003 |
Approved |
no |
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Is ISI |
yes |
International Collaboration |
yes |
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Call Number |
IFIC @ pastor @ |
Serial |
3139 |
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Author |
Caballero-Folch, R. et al; Domingo-Pardo, C.; Agramunt, J.; Algora, A.; Rubio, B.; Tain, J.L. |
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Title |
beta-decay half-lives and beta-delayed neutron emission probabilities for several isotopes of Au, Hg, Tl, Pb, and Bi, beyond N=126 |
Type |
Journal Article |
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Year |
2017 |
Publication |
Physical Review C |
Abbreviated Journal |
Phys. Rev. C |
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Volume |
95 |
Issue |
6 |
Pages |
064322 - 16pp |
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Keywords |
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Abstract |
Background: There have been measurements on roughly 230 nuclei that are beta-delayed neutron emitters. They range from He-8 up to La-150. Apart from 210Tl, with a branching ratio of only 0.007%, no other neutron emitter has been measured beyond A = 150. Therefore, new data are needed, particularly in the region of heavy nuclei around N = 126, in order to guide theoretical models and help understand the formation of the third r-process peak at A similar to 195. Purpose: To measure both beta-decay half-lives and neutron branching ratios of several neutron-rich Au, Hg, Tl, Pb, and Bi isotopes beyond N = 126. Method: Ions of interest were produced by fragmentation of a U-238 beam, selected and identified via the GSI-FRS fragment separator. A stack of segmented silicon detectors (SIMBA) was used to measure ion implants and beta decays. An array of 30 He-3 tubes embedded in a polyethylene matrix (BELEN) was used to detect neutrons with high efficiency and selectivity. A self-triggered digital system is employed to acquire data and to enable time correlations. The latter were analyzed with an analytical model and results for the half-lives and neutron-branching ratios were derived by using the binned maximum-likelihood method. Results: Twenty new beta-decay half-lives are reported for Au204-206, Hg208-211, Tl211-216, Pb215-218, and Bi218-220, nine of them for the first time. Neutron emission probabilities are reported for Hg-210,Hg-211 and Tl211-216. Conclusions: The new beta-decay half-lives are in good agreement with previous measurements on nuclei in this region. The measured neutron emission probabilities are comparable to or smaller than values predicted by global models such as relativistic Hartree Bogoliubov plus the relativistic quasi-particle random phase approximation (RHB + RQRPA). |
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Address |
[Caballero-Folch, R.; Calvino, F.; Cortes, G.; Gomez-Hornillos, M. B.; Riego, A.] Univ Politecn Cataluna, DFEN, INTE, E-08028 Barcelona, Spain, Email: rcaballero-folch@triumf.ca |
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Publisher |
Amer Physical Soc |
Place of Publication |
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Language |
English |
Summary Language |
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Original Title |
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Series Editor |
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Series Title |
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Abbreviated Series Title |
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Series Volume |
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Series Issue |
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Edition |
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ISSN |
2469-9985 |
ISBN |
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Medium |
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Area |
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Expedition |
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Conference |
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Notes |
WOS:000404022100001 |
Approved |
no |
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Is ISI |
yes |
International Collaboration |
yes |
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Call Number |
IFIC @ pastor @ |
Serial |
3176 |
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Author |
BRIKEN Collaboration (Tarifeño-Saldivia, A. et al); Tain, J.L.; Domingo-Pardo, C.; Agramunt, J.; Algora, A.; Morales, A.I.; Rubio, B.; Tolosa, A. |
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Title |
Conceptual design of a hybrid neutron-gamma detector for study of beta-delayed neutrons at the RIB facility of RIKEN |
Type |
Journal Article |
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Year |
2017 |
Publication |
Journal of Instrumentation |
Abbreviated Journal |
J. Instrum. |
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Volume |
12 |
Issue |
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Pages |
P04006 - 22pp |
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Keywords |
Detector modelling and simulations I (interaction of radiation with matter, interaction; of photons with matter, interaction of hadrons with matter, etc); Instrumentation for radioactive beams (fragmentation devices; fragment and isotope, separators incl. ISOL; isobar separators; ion and atom traps; weak-beam diagnostics; radioactive-beam ion sources); Neutron detectors (cold, thermal, fast neutrons) |
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Abstract |
BRIKEN is a complex detection system to be installed at the RIB-facility of the RIKEN Nishina Center. It is aimed at the detection of heavy-ion implants, β-particles, γ-rays and β-delayed neutrons. The whole detection setup involves the Advanced Implantation Detection Array (AIDA), two HPGe Clover detectors and a large set of 166 counters of 3He embedded in a high-density polyethylene matrix. This article reports on a novel methodology developed for the conceptual design and optimisation of the 3He-tubes array, aiming at the best possible performance in terms of neutron detection. The algorithm is based on a geometric representation of two selected parameters of merit, namely, average neutron detection efficiency and efficiency flatness, as a function of a reduced number of geometric variables. The response of the detection system itself, for each configuration, is obtained from a systematic MC-simulation implemented realistically in Geant4. This approach has been found to be particularly useful. On the one hand, due to the different types and large number of 3He-tubes involved and, on the other hand, due to the additional constraints introduced by the ancillary detectors for charged particles and gamma-rays. Empowered by the robustness of the algorithm, we have been able to design a versatile detection system, which can be easily re-arranged into a compact mode in order to maximize the neutron detection performance, at the cost of the gamma-ray sensitivity. In summary, we have designed a system which shows, for neutron energies up to 1(5) MeV, a rather flat and high average efficiency of 68.6%(64%) and 75.7%(71%) for the hybrid and compact modes, respectively. The performance of the BRIKEN system has been also quantified realistically by means of MC-simulations made with different neutron energy distributions. |
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Address |
[Tarifeno-Saldivia, A.] UPC, Barcelona, Spain, Email: ariel.esteban.tarifeno@upc.edu |
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Corporate Author |
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Thesis |
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Publisher |
Iop Publishing Ltd |
Place of Publication |
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Language |
English |
Summary Language |
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Original Title |
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Series Editor |
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Series Title |
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Abbreviated Series Title |
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Series Volume |
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Series Issue |
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Edition |
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ISSN |
1748-0221 |
ISBN |
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Medium |
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Area |
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Expedition |
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Conference |
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Notes |
WOS:000405067800006 |
Approved |
no |
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Is ISI |
yes |
International Collaboration |
yes |
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Call Number |
IFIC @ pastor @ |
Serial |
3209 |
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Author |
n_TOF Collaboration (Sabate-Gilarte et al.); Domingo-Pardo, C.; Tain, J.L.; Tarifeño-Saldivia, A. |
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Title |
High-accuracy determination of the neutron flux in the new experimental area n_TOF-EAR2 at CERNx |
Type |
Journal Article |
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Year |
2017 |
Publication |
European Physical Journal A |
Abbreviated Journal |
Eur. Phys. J. A |
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Volume |
53 |
Issue |
10 |
Pages |
210 - 13pp |
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Keywords |
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Abstract |
A new high flux experimental area has recently become operational at the nTOF facility at CERN. This new measuring station, nTOF-EAR2, is placed at the end of a vertical beam line at a distance of approximately 20m from the spallation target. The characterization of the neutron beam, in terms of flux, spatial profile and resolution function, is of crucial importance for the feasibility study and data analysis of all measurements to be performed in the new area. In this paper, the measurement of the neutron flux, performed with different solid-state and gaseous detection systems, and using three neutronconverting reactions considered standard in different energy regions is reported. The results of the various measurements have been combined, yielding an evaluated neutron energy distribution in a wide energy range, from 2meV to 100MeV, with an accuracy ranging from 2%, at low energy, to 6% in the high-energy region. In addition, an absolute normalization of the n_TOF-EAR2 neutron flux has been obtained by means of an activation measurement performed with 197 Au foils in the beam. |
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Address |
[Sabate-Gilarte, M.; Vlachoudis, V.; Aberle, O.; Bacak, M.; Brugger, M.; Calviani, M.; Cardella, R.; Cerutti, F.; Chiaveri, E.; Ferrari, A.; Hernandez-Prieto, A.; Kadi, Y.; Losito, R.; Macina, D.; Mingrone, F.; Montesano, S.; Rubbia, C.; Weiss, C.] CERN, European Org Nucl Res, Geneva, Switzerland, Email: massimo.barbagallo@ba.infn.it |
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Corporate Author |
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Thesis |
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Publisher |
Springer |
Place of Publication |
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Editor |
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Language |
English |
Summary Language |
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Original Title |
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Series Editor |
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Series Title |
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Abbreviated Series Title |
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Series Volume |
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Series Issue |
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Edition |
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ISSN |
1434-6001 |
ISBN |
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Area |
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Expedition |
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Conference |
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Notes |
WOS:000413766400002 |
Approved |
no |
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Is ISI |
yes |
International Collaboration |
yes |
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Call Number |
IFIC @ pastor @ |
Serial |
3350 |
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Author |
n_TOF Collaboration (Wright, T. et al); Domingo-Pardo, C.; Giubrone, G.; Tain, J.L.; Tarifeño-Saldivia, A. |
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Title |
Measurement of the U-238(n,gamma) cross section up to 80 keV with the Total Absorption Calorimeter at the CERN n_TOF facility |
Type |
Journal Article |
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Year |
2017 |
Publication |
Physical Review C |
Abbreviated Journal |
Phys. Rev. C |
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Volume |
96 |
Issue |
6 |
Pages |
064601 - 11pp |
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Keywords |
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Abstract |
The radiative capture cross section of a highly pure (99.999%), 6.125(2) grams and 9.56(5) x 10(-4) atoms/barn areal density U-238 sample has been measured with the Total Absorption Calorimeter (TAC) in the 185 m flight path at the CERN neutron time-of-flight facility n_TOF. This measurement is in response to the NEA High Priority Request list, which demands an accuracy in this cross section of less than 3% below 25 keV. These data have undergone careful background subtraction, with special care being given to the background originating from neutrons scattered by the 238U sample. Pileup and dead-time effects have been corrected for. The measured cross section covers an energy range between 0.2 eV and 80 keV, with an accuracy that varies with neutron energy, being better than 4% below 25 keV and reaching at most 6% at higher energies. |
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Address |
[Wright, T.; Billowes, J.; Ryan, J. A.; Ware, T.] Univ Manchester, Manchester, Lancs, England, Email: tobias.wright@manchester.ac.uk |
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Corporate Author |
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Thesis |
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Publisher |
Amer Physical Soc |
Place of Publication |
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Editor |
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Language |
English |
Summary Language |
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Original Title |
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Series Editor |
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Series Title |
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Abbreviated Series Title |
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Series Volume |
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Series Issue |
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Edition |
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ISSN |
2469-9985 |
ISBN |
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Medium |
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Area |
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Expedition |
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Conference |
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Notes |
WOS:000416848700005 |
Approved |
no |
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Is ISI |
yes |
International Collaboration |
yes |
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Call Number |
IFIC @ pastor @ |
Serial |
3392 |
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| Permanent link to this record |
